You could end up being there a while with not a whole lot of breaks, try to eat and drink as much as you can if weigh-ins arent an issue. You should be fine
Don’t do it. I haven’t spotted and loaded but have run a number of meets. It can be a long, grueling day for the platform crew. Not only are you lifting all day, it has to be fast and it has to be right. I would never expect a lifter to spot/load the day before they lift. If you’re committed to helping, there are usually a number of other jobs going like head table or keeping the warm up room in decent order.
I’m late to the party, but yeah I would not do it. I ended up spotting at a meet for 12 hours with no breaks. That included break down the equipment and catching numerous benches/squats. By the end of the day I was dead.